This proposal requests funds for the support of three projects in the area of perinatal androgenization and psychosexual differentiation of the rat. 1) The objective of the first project is to observe hooded rats with four different histories of exposure to perinatal androgen (adult castrated normal male rats, males castrated at birth but exposed to prenatal androgens, post-natally androgenized females ovariectomized as adults, and normal females ovariectomized as adults both with and without estrous induction in a mini-environment. This environment features a) familiarity of both members of the mating pair with the apparatus, b) a familiar escape route for the experimental animal which leads to its home cage (burrow equivalent). While in the apparatus, sexual, agonistic, flight, and sniffing behaviors will be video-taped, and later examined in detail for both male, female, and dyadic patterns. 2) The objective of the second project is to develop techniques for intrauterine castration of male and female rats and intrafetal implantation of testosterone propionate into male and female fetuses. 3) The objective of the third project is to finish data collection and analyze data for publication. The project to be reported involves comparing the sexual and social behaviors of the four perinatal androgen treatment groups listed in project one after bilateral olfactory bulb ablation.